JP7165464B2 - Organic film deposition method - Google Patents

Description

The present invention relates to a film forming method for forming an organic film using a raw material solution.

2. Description of the Related Art In recent years, as thin films used in next-generation devices for various applications, application of organic thin films instead of inorganic thin films has been actively studied. The reasons for this are that organic thin films can be formed using relatively inexpensive film-forming methods such as coating or printing, and that bendable organic devices can be realized using the flexibility of organic thin films. etc. As a device using an organic thin film, for example, an organic EL using a light-emitting organic compound as an image display element and the like can be mentioned. An organic EL element emits light by recombination of electrons and holes (carriers) injected into the organic thin film from the electrodes on both sides by providing electrodes on both sides of a thin film made of an organic material and applying a voltage between the electrodes. This is a current-driven light-emitting device that utilizes In order to put such devices using organic thin films into practical use, it is necessary to form organic thin films having excellent properties and heat resistance, as well as facilitating manufacturing and reducing costs. However, there is a problem that the characteristics of the organic thin film degrade over time, especially in a high-temperature environment.

Methods for forming an organic thin film include a dry process typified by a vacuum deposition method and a wet process typified by a spin coating method. The dry process has advantages such as easy control of the film thickness and the possibility of different coatings using a layered structure of different materials and a mask with appropriate openings. cannot be used, and there is a problem that the apparatus is large and costly. On the other hand, the wet process can be applied to polymer materials and thermally unstable substances, and has the advantage of being a process suitable for mass production because the equipment is simple. There is a drawback that the flatness of the substrate is particularly required.

As a method for forming an organic thin film by a wet process, for example, in Patent Document 1, a raw material solution of an organic material is once aerosolized, the solvent in the aerosol is vaporized to form organic material fine particles, and the fine particles are applied to a substrate. It is described that an organic thin film is formed by spraying on. However, in the method described in Patent Document 1, the film is formed by the collision energy when the organic material fine particles are sprayed onto the substrate. There is a problem that the characteristics are degraded and the collision adversely affects the substrate. In addition, the film obtained by the method described in Patent Document 1 does not have a level of heat resistance that is practically sufficient, and there is a problem that the characteristics of the organic thin film gradually deteriorate due to deterioration over time due to heat at high temperatures. was there.

Further, in Patent Document 2, a mist of a composition for forming an organic thin film is formed by dissolving or dispersing an organic material in a solvent, the obtained mist is heated, and the heated mist is irradiated onto a substrate. It describes drying the mist-deposited film after deposition to form an organic thin film. However, with the method described in Patent Document 2, it is difficult to obtain a film that is homogeneous and has excellent adhesion, and furthermore, in a high-temperature environment, there is a problem that the properties of the organic thin film deteriorate over time due to heat. , the heat resistance and thermal stability were not fully satisfactory.

Therefore, there has been a long-awaited method for industrially advantageous formation of an organic film that does not have the above-described problems, is inhibited from being deteriorated over time due to heat in a high-temperature environment, and has excellent thermal stability.

Japanese Patent Application Laid-Open No. 2002-075641 JP-A-2005-158954

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel film forming method capable of forming an organic film having excellent thermal stability, which is suppressed from being deteriorated over time due to heat in a high-temperature environment, and which is industrially advantageous. .

As a result of intensive studies to achieve the above object, the present inventors have found that a raw material solution containing at least an organic compound and a solvent is atomized or dropletized, and the obtained mist or droplets are used to form an organic film on a substrate. wherein the solvent has a boiling point of 150° C. or higher, and the film is formed by thermally reacting the mist or the droplets on the substrate at a temperature higher than the boiling point of the solvent, We have found that it is possible to simply and easily form an organic film having high film-forming quality, suppressing deterioration of properties due to heat in a high-temperature environment over time, and having excellent thermal stability. However, it has been found that the conventional problems described above can be solved at once.
Moreover, after obtaining the above knowledge, the inventors of the present invention conducted further studies and completed the present invention.

Specifically, the present invention relates to the following inventions.
[1] A method of forming an organic film on a substrate by atomizing or dropletizing a raw material solution containing at least an organic compound and a solvent, and using the obtained mist or droplets, wherein the boiling point of the solvent is 150° C. or higher, and the film formation is performed by thermally reacting the mist or the droplets on the substrate at a temperature higher than the boiling point of the solvent.
[2] The film forming method according to [1], wherein the solvent is a cyclic compound.
[3] The film forming method according to [1] or [2], wherein the solvent is a heterocyclic compound.
[4] The film forming method according to any one of [1] to [3], wherein the solvent has a boiling point of 200° C. or higher.
[5] The film forming method according to any one of [1] to [4], wherein the organic compound is a polymer compound.
[6] The film forming method according to any one of [1] to [5], wherein the organic compound is a conjugated polymer compound.
[7] The film formation method according to any one of [1] to [6], wherein the thermal reaction is performed at a temperature of 240° C. or higher.
[8] The film formation method according to any one of [1] to [7], wherein the atomization or droplet formation is performed using ultrasonic vibration.
[9] The film forming method according to any one of [1] to [8], wherein the thermal reaction is performed under atmospheric pressure.

According to the film forming method of the present invention, it is possible to industrially form an organic film having excellent thermal stability by suppressing deterioration over time due to heat in a high-temperature environment.

1 is a schematic configuration diagram of a film forming apparatus used in Examples. FIG. It is a figure which shows the result of fluorescence spectrum measurement in an Example. It is a figure which shows the result of fluorescence spectrum measurement in a comparative example.

A method of forming an organic film on a substrate by atomizing or dropletizing a raw material solution containing at least an organic compound and a solvent (atomization/droplet forming step), and using the obtained mist or droplets. , the boiling point of the solvent is 150° C. or higher, and the film formation is performed by thermally reacting the mist or the droplets on the substrate at a temperature equal to or higher than the boiling point of the solvent (film formation step). and

(substrate)
The substrate is not particularly limited as long as it can support the film to be deposited. The material of the substrate is also not particularly limited as long as it does not interfere with the object of the present invention, and may be a known substrate, an organic compound, or an inorganic compound. It may be a porous structure.

A substrate having at least one film selected from a metal film, a semiconductor film, a conductive film and an insulating film formed on part or all of the surface can also be suitably used as the substrate. The constituent metal of the metal film is, for example, one selected from gallium, iron, indium, aluminum, vanadium, titanium, chromium, rhodium, nickel, cobalt, zinc, magnesium, calcium, silicon, yttrium, strontium and barium, or Two or more kinds of metals and the like are included. Examples of constituent materials of the semiconductor film include simple elements such as silicon and germanium, compounds containing elements of Groups 3 to 5 and Groups 13 to 15 of the periodic table, metal oxides, and metal sulfides. , metal selenide, or metal nitride. Examples of materials constituting the conductive film include tin-doped indium oxide (ITO), fluorine-doped indium oxide (FTO), zinc oxide (ZnO), aluminum-doped zinc oxide (AZO), and gallium-doped zinc oxide (GZO). , tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ), and tungsten oxide (WO ₃ ). More preferably, it is an indium oxide (ITO) film. Materials constituting the insulating film include, for example, aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ), silicon oxynitride (Si ₄ O ₅ N ₃ ) and the like.

The means for forming the metal film, the semiconductor film, the conductive film, and the insulating film is not particularly limited, and known means may be used. Examples of such forming means include mist CVD method, sputtering method, CVD method (vapor phase growth method), SPD method (spray pyrolysis deposition method), vapor deposition method, ALD (atomic layer deposition) method, coating method ( For example, dipping, dropping, doctor blade, inkjet, spin coating, brush coating, spray coating, roll coater, air knife coating, curtain coating, wire bar coating, gravure coating, inkjet coating, etc.).

The shape of the substrate may be any shape, and is effective for all shapes. Cylindrical, helical, spherical, ring-shaped, etc. are mentioned, and in the present invention, a substrate is preferred. The thickness of the substrate is not particularly limited in the present invention, but is preferably 0.5 μm to 100 mm, more preferably 1 μm to 10 mm. The substrate is plate-shaped and is not particularly limited as long as it serves as a support for the film to be deposited. It may be an insulator substrate, a semiconductor substrate, a metal substrate, or a conductive substrate. In the present invention, the substrate is preferably a glass substrate.

(Atomization/dropletization process)
In the atomization/droplet formation step, the raw material solution is atomized or dropletized. The atomization means or dropletization means is not particularly limited as long as it can atomize or dropletize the raw material solution, and may be a known means, but in the present invention, atomization means using ultrasonic vibration Alternatively, a dropletizing means is preferred. The mist or droplets obtained using ultrasonic vibrations have an initial velocity of zero and float in the air, so they are preferable. It is very suitable because it is a mist that can be used to prevent damage due to collision energy. The droplet size is not particularly limited, and may be droplets of several millimeters, preferably 50 μm or less, more preferably 100 nm to 10 μm.

(raw material solution)
The raw material solution contains at least an organic compound and a solvent, and is not particularly limited as long as it can be atomized or dropletized. The raw material solution may further contain an inorganic material or an organic material as long as the object of the present invention is not hindered. Moreover, the raw material solution may further contain both inorganic materials and organic materials.

The organic compound is not particularly limited, and may be a known organic compound. It may be a low-molecular-weight compound or a high-molecular-weight compound. In the present invention, it is preferable that the organic compound is a polymer compound, since the organic film can be formed more satisfactorily. Here, a high-molecular weight compound means a compound having a molecular weight of, for example, 10,000 or more, and a low-molecular-weight compound means a compound having a molecular weight of, for example, less than 10,000. Examples of the low-molecular-weight compounds include polyacene compounds such as anthracene, naphthalene, pyrene, naphthacene, tetracene, pentacene, benzopentacene, dibenzopentacene, tetrabenzopentacene, naphthpentacene, hexacene, heptacene, nanoacene; phenanthrene, picene, fulminene, pyrene, coronene compounds such as antanthrene, peropyrene, coronene, benzocoronene, dibenzocoronene, hexabenzocoronene, benzodicoronene, and vinylcoronene; perylene compounds such as perylene, terrylene, diperylene, and quaterrylene; tetrathiafulvalene compounds, quinone compounds, tetracyanoquinodimethane compounds , trinaphthine, heptaphene, ovalene, rubicene, violanthrone, isoviolanthrone, chrysene, circumanthracene, bisanthene, zethrene, heptazethrene, pyranthrene, violanthen, isoviolanthene, biphenyl, triphenylene, terphenyl, quarterphenyl, circobiphenyl, Kekulene, phthalocyanine, porphyrin, fullerene (C60, C70), polythiophene oligomer, polypyrrole oligomer, polyphenylene oligomer, polyphenylene vinylene oligomer, polythienylene vinylene oligomer, copolymer oligomer of thiophene and phenylene, thiophene and fluorene and copolymer oligomers or derivatives thereof.

Examples of the polymer compound include conjugated polymer compounds and non-conjugated polymer compounds. Examples of the conjugated polymer compound include polythiophene-based compounds, polypyrrole-based compounds, polyindole-based compounds, polycarbazole-based compounds, polyaniline-based compounds, polyacetylene-based compounds, polyfuran-based compounds, polyparaphenylene vinylene-based compounds, and polyazulene-based compounds. compounds, polyparaphenylene-based compounds, polyparaphenylene sulfide-based compounds, polyisothianaphthene-based compounds, polythiazyl-based compounds, derivatives thereof, and the like. Examples of the non-conjugated polymer compound include polyethylene, polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, poly(N-vinylcarbazole), and hydrocarbon resins. , ketone resin, phenoxy resin, polyamide, ethyl cellulose, vinyl acetate, ABS resin, polyurethane, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin, silicone resin and the like. In the present invention, the polymer compound is preferably a conjugated polymer compound, more preferably a polyparaphenylene vinylene compound. Specific examples of the poly-paraphenylene vinylene compound include, for example, poly(2,5-dialkoxy-para-phenylene vinylene) (RO-PPV), cyano-substituted-poly(para-phenvinylene) (CN -PPV), poly(2-dimethyloctylsilyl-para-phenylene vinylene) (DMOS-PPV) or poly(2-methoxy, 5-(2'-ethylhexoxy)-para-phenylene vinylene) (MEH-PPV), etc. mentioned.

The mixing ratio of the organic compound in the raw material solution is not particularly limited, but is preferably 0.001% by weight to 80% by weight, more preferably 0.01% by weight to 80% by weight.

The solvent is not particularly limited as long as it has a boiling point of 150° C. or higher, and may be a cyclic compound or an acyclic compound. In the present invention, the solvent is preferably a cyclic compound, more preferably a heterocyclic compound, because the raw material solution can be obtained with better atomization or droplet formation. In the present invention, the boiling point of the solvent is preferably 180° C. or higher, and more preferably 200° C. or higher, because the organic film can be obtained with more excellent thermal stability. . The upper limit of the boiling point of the solvent is also not particularly limited, but in the present invention, it is preferably 300° C. or lower, more preferably 250° C. or lower. Here, the boiling point means the boiling point under atmospheric pressure.

Suitable examples of the cyclic compound include, but are not limited to, aromatic hydrocarbons, aromatic alcohols, and heterocyclic compounds (such as cyclic ester compounds, cyclic amide compounds, and cyclic ketone compounds). Examples of the aromatic hydrocarbons include alkylbenzenes such as trimethylbenzenes, ethyltoluenes, ethylxylenes, diethylbenzenes, and propylbenzenes, or methylnaphthalenes such as 1-methylnaphthalene, ethylnaphthalenes, and dimethylnaphthalene. and alkylnaphthalenes such as tetraline, alkylbiphenyls, alkylanthracenes, and the like. Examples of the aromatic alcohol include benzyl alcohol, o-tolylmethanol, m-tolylmethanol, p-tolylmethanol, 1-phenylethanol, 2-phenylethanol, 1-phenyl-1-propanol, 1-phenyl-2 -propanol, or 3-phenyl-1-propanol. Examples of the cyclic ester compound include β-lactone with a 4-membered ring structure, γ-lactone with a 5-membered ring structure, δ-lactone with a 6-membered ring structure, and ε-lactone with a 7-membered ring structure. Specifically, for example, β-butyrolactone, γ-butyrolactone, γ-valerolactone, γ-hexalactone, γ-heptalactone, γ-octalactone, γ-nonalactone, γ-decalactone, γ-undecalactone, δ -valerolactone, delta-hexalactone, delta-heptalactone, delta-octalactone, delta-nonalactone, delta-decalactone, delta-undecalactone or epsilon-caprolactone. Examples of the cyclic amide compound include β-lactams with a 4-membered ring structure, γ-lactams with a 5-membered ring structure, δ-lactams with a 6-membered ring structure, and ε-lactams with a 7-membered ring structure. Specifically, for example, β-butyrolactam, γ-butyrolactam, γ-valerolactam, γ-hexalactam, γ-heptalactam, γ-octalactam, γ-nonalactam, γ-decalactam, γ-undecalactam, δ -valerolactam, delta-hexalactam, delta-heptalactam, delta-octalactam, delta-nonalactam, delta-decalactam, delta-undecalactam, epsilon-caprolactam, N-methyl-2-pyrrolidone, N-ethyl-2 -pyrrolidone, N-propyl-2-pyrrolidone, N-octyl-2-pyrrolidone, and the like. Examples of the cyclic ketone compound include cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, cyclodecanone, and the like. In the present invention, the solvent is preferably a heterocyclic compound, more preferably a cyclic ester compound or a cyclic amide compound, most preferably a cyclic amide compound.

The mixing ratio of the solvent in the raw material solution is not particularly limited, but is preferably 0.001 mol % and 99 mol %, more preferably 0.01 mol % to 99 mol %.

The raw material solution may further contain an additive. The additive is not particularly limited as long as it does not interfere with the object of the present invention, and may be an acid, a base, a solvent, or the like, and may be a known additive. It may be an inorganic material or an organic material. Examples of the acid include hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, nitric acid, acetic acid, carbonic acid, formic acid, benzoic acid, chlorous acid, hypochlorous acid, sulfurous acid, Sulfurous acid, nitrous acid, hyponitrous acid, phosphorous acid, protonic acid such as hypophosphorous acid, or mixtures thereof. Examples of the base include sodium hydroxide, potassium hydroxide, calcium hydroxide, and mixtures thereof. The solvent is not particularly limited as long as it does not interfere with the object of the present invention, and may be an organic solvent or an inorganic solvent. A mixed solvent of an organic solvent and an inorganic solvent may be used. Examples of the organic solvent include alcohols, esters, ethers and the like. Examples of the inorganic solvent include water, and more specific examples include pure water, ultrapure water, tap water, well water, mineral spring water, mineral water, hot spring water, spring water, fresh water, and seawater.

In the present invention, it is preferable to supply a carrier gas to the mist or the droplets and carry the mist or the droplets to the substrate with the carrier gas. The carrier gas is not particularly limited as long as it does not interfere with the object of the present invention. Suitable examples include oxygen, ozone, inert gases such as nitrogen and argon, and reducing gases such as hydrogen gas and forming gas. mentioned. In addition, although one type of carrier gas may be used, two or more types may be used, and a diluted gas with a reduced flow rate (for example, a 10-fold diluted gas, etc.) may be further used as a second carrier gas. good too. In addition, the carrier gas may be supplied at two or more locations instead of at one location. Although the flow rate of the carrier gas is not particularly limited, it is preferably 0.01 to 20 L/min, more preferably 1 to 10 L/min. In the case of diluent gas, the flow rate of diluent gas is preferably 0.001 to 2 L/min, more preferably 0.1 to 1 L/min.

(Film formation process)
In the film forming step, a film is formed on the substrate by thermally reacting the mist or the droplets on the substrate at a temperature equal to or higher than the boiling point of the solvent. The thermal reaction is not particularly limited as long as the mist or liquid droplets react with heat, and the reaction conditions and the like are not particularly limited as long as the objects of the present invention are not hindered. The temperature of the thermal reaction is not particularly limited as long as it is a temperature equal to or higher than the boiling point of the solvent. , preferably 240° C. or higher. Further, in the present invention, the temperature of the thermal reaction is preferably 8° C. or more higher than the boiling point of the solvent, because the film can be formed more satisfactorily, and is preferably 30° C. or more. is more preferred. The upper limit of the temperature of the thermal reaction is also not particularly limited, but it is preferably 350° C. or lower, more preferably 300° C. or lower. The thermal reaction may be carried out under vacuum, non-oxygen atmosphere, reducing gas atmosphere or oxygen atmosphere as long as the object of the present invention is not impaired. It is preferably carried out in an oxygen atmosphere. Also, the reaction may be carried out under atmospheric pressure, increased pressure or reduced pressure, but in the present invention, it is preferably carried out under atmospheric pressure. Note that the film thickness can be set by adjusting the film formation time. Further, for example, when a linear source type film forming apparatus is used, the film thickness can be appropriately set by adjusting the number of scan reciprocations for film formation. Further, for example, when a roll-to-roll film forming apparatus is used, the film thickness can be appropriately set by adjusting the number of nozzles or the like.

In the present invention, an annealing treatment may be performed after the film formation. Annealing treatment temperature is not particularly limited as long as the object of the present invention is not impaired, and is usually 50°C to 650°C, preferably 100°C to 300°C. The annealing treatment time is usually 1 minute to 48 hours, preferably 10 minutes to 24 hours, more preferably 30 minutes to 12 hours. The annealing treatment may be performed in any atmosphere as long as it does not impede the purpose of the present invention, but in the present invention, it is preferably performed in a non-oxygen atmosphere, and preferably in a nitrogen atmosphere. more preferred.

In the present invention, the film may be formed directly on the substrate, or may be formed via another layer such as a buffer layer (buffer layer) or stress relaxation layer. Methods for forming other layers such as buffer layers (buffer layers) and stress relaxation layers are not particularly limited, and known methods may be used. In the present invention, mist CVD method or mist deposition method is preferable.

By forming the film as described above, deterioration over time due to heat in a high-temperature environment is suppressed, and an organic film having excellent thermal stability can be industrially advantageously obtained.

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these.

(Example 1)
1. Film Forming Apparatus A film forming apparatus 1 used in this example will be described with reference to FIG. The film forming apparatus 1 includes a carrier gas source 2a for supplying a carrier gas, a flow control valve 3a for adjusting the flow rate of the carrier gas sent from the carrier gas source 2a, and a carrier gas (dilution) for supplying the carrier gas (dilution). dilution) supply source 2b, flow control valve 3b for adjusting the flow rate of carrier gas (dilution) sent from carrier gas (dilution) supply means 2b, mist generation source 4 containing raw material solution 4a, water A container 5 containing 5a, an ultrasonic transducer 6 attached to the bottom surface of the container 5, a hot plate 8, a substrate 10 placed on the hot plate 8, and from the mist generating source 4 to the vicinity of the substrate 10. It is provided with a supply pipe 9 and a nozzle 7 that connect the

2. Preparation of Raw Material Solution 2-Methoxy, 5-(2′-ethylhexoxy)-para-phenylenevinylene (MEH-PPV) was mixed with N-methyl-2-pyrrolidone (boiling point: 202° C.) to obtain a raw material solution. .

3. Preparing for film formation 2 above. The raw material solution 4 a obtained in 1. was accommodated in the mist generation source 4 . Next, a glass/ITO substrate was placed on the hot plate 8 as the substrate 10, and the hot plate 8 was operated to raise the temperature of the substrate 10 to 240.degree. Next, the flow control valves 3a and 3b are opened to set the flow rate of the carrier gas supplied from the carrier gas supply source 2a to 4.0 L/min, and the carrier gas (dilution) supplied from the carrier gas (dilution) 2b. The flow rate was adjusted to 4.0 L/min. Nitrogen was used as a carrier gas.

4. Formation of Organic Film Next, the ultrasonic oscillator 6 is vibrated at 2.4 MHz, and the vibration is propagated through the water 5a to the raw material solution 4a, thereby atomizing the raw material solution 4a to generate mist 4b. rice field. A carrier gas is supplied to the mist 4b, and the carrier gas conveys the mist 4b through the supply pipe 9 to the substrate 10, where the mist 4b is heated in the vicinity of the substrate 10 at 240° C. under atmospheric pressure. thermally reacted to form an organic film on the substrate 10 .

5. Evaluation 4 above. Fluorescence spectrum measurement was performed on the organic film obtained in . The results are shown in FIG. As can be seen from FIG. 2, the obtained organic film had an emission peak in the wavelength range of 350 to 400 nm, and was excellent in emission characteristics.

(Thermal stability evaluation)
4 above. Thermal stability was evaluated for the organic film obtained in . Specifically, the obtained organic film was heated at a temperature of 240° C., and the state of the film after heating was evaluated by performing fluorescence spectrum measurement. FIG. 2 shows the results of fluorescence spectrum measurement after heating for 4 hours. As is clear from FIG. 2, the peak positions and peak intensities of the fluorescence spectra were substantially the same before and after the heat treatment. Also, when the heat treatment time was set to 8 hours, the same results as in the case of the heat treatment time of 4 hours were obtained. From this, it can be seen that the obtained film does not deteriorate with time due to heat and maintains the properties of the film, and is excellent in thermal stability.

(Example 2)
An organic film was obtained in the same manner as in Example 1, except that the film formation temperature was 210°C. The obtained film was subjected to fluorescence spectrum measurement in the same manner as in Example 1. As a result, the obtained film had an emission peak in the wavelength range of 350 to 400 nm, similarly to the film obtained in Example 1, and was a film with excellent emission characteristics. In addition, the obtained film was subjected to thermal stability evaluation in the same manner as in Example 1. The obtained film did not deteriorate over time due to heat, and the film properties were maintained. Excellent stability.

(Comparative example 1)
An organic film was obtained in the same manner as in Example 1, except that toluene (boiling point: 110.6° C.) was used as the solvent instead of N-methyl-2-pyrrolidone. Fluorescence spectrum measurement was performed on the obtained film in the same manner as in Example 1, and the peak intensity of the fluorescence spectrum of the film was ⅕ or less that of the film obtained in Example 1.

(Comparative example 2)
An organic film was obtained in the same manner as in Example 1, except that the film formation temperature was 180°C. The obtained film was subjected to fluorescence spectrum measurement in the same manner as in Example 1. The results are shown in FIG. As can be seen from FIG. 3, the obtained film had an emission peak in the wavelength range of 350-400 nm. In addition, the obtained film was evaluated for thermal stability in the same manner as in Example 1. FIG. 3 shows the results of fluorescence spectrum measurement after heat treatment for 4 hours and 8 hours. As can be seen from FIG. 3, the peak intensity of the fluorescence spectrum of the film was reduced to about ⅓ by the heat treatment for 4 hours, and the peak of the fluorescence spectrum could not be observed after the heat treatment for 8 hours.

The film forming method of the present invention can suppress deterioration over time due to heat in a high-temperature environment and can form an organic film having excellent thermal stability, which is industrially advantageous. available in the field. Moreover, the organic film obtained by using the film forming method of the present invention can be suitably used for, for example, an organic light-emitting device.

REFERENCE SIGNS LIST 1 film forming apparatus 2a carrier gas source 2b carrier gas (dilution) source 3a flow control valve 3b flow control valve 4 mist generation source 4a raw material solution 4b mist 5 container 5a water 6 ultrasonic vibrator 7 nozzle 8 hot plate 9 supply pipe 10 substrate

Claims (9)

A method of forming an organic film on a substrate by atomizing or dropletizing a raw material solution containing at least an organic compound and a solvent, and using the obtained mist or droplets, wherein the solvent has a boiling point of 150° C. or higher. wherein the film formation is performed by thermally reacting the mist or the droplets on the substrate at a temperature equal to or higher than the boiling point of the solvent. 2. The film forming method according to claim 1, wherein the solvent is a cyclic compound. 3. The film forming method according to claim 1, wherein the solvent is a heterocyclic compound. The film forming method according to any one of claims 1 to 3, wherein the solvent has a boiling point of 200°C or higher. The film forming method according to any one of claims 1 to 4, wherein the organic compound is a polymer compound. The film forming method according to any one of claims 1 to 5, wherein the organic compound is a conjugated polymer compound. The film forming method according to any one of claims 1 to 6, wherein the thermal reaction is performed at a temperature of 240°C or higher. The film forming method according to any one of claims 1 to 7, wherein the atomization or droplet formation is performed using ultrasonic vibration. The film forming method according to any one of claims 1 to 8, wherein the thermal reaction is performed under atmospheric pressure.

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